1. Field of the Invention
The present invention relates to a zoom lens device and, in particular, to a zoom lens device which is capable of varying magnification and focusing by moving part of an optical system.
2. Description of the Related Art
Conventionally, as shown in FIG. 10, a general video tape recorder (which is hereinafter referred to as VTR) has a lens barrel 8 in which a lens 10, a lens frame 12, guide shafts 14, 14, a cam ring 16, a fixed lens barrel 18, and actuators 20, 22 are arranged in this order starting from an optical axis L to the outer side of the lens barrel 8.
In the above structure, because the cam ring 16 is disposed in the fixed lens barrel 18, the fixed lens barrel is made to have a large diameter. For this reason, as shown in FIG. 10, if the side portion of the the fixed lens barrel 18 is fixed to the outer case of a main body of a camera, a mechanical deck or the like, then the projecting dimension of the lens barrel from a main body 24 of the VTR becomes great, which results in a poor space efficiency (as shown in FIG. 11) and thus makes it difficult to reduce the VTR to a compact size.
Also, in order that the conventional lens barrel using the cam ring 16 can be made compact, the respective components of the lens barrel must be reduced in size. However, such size reduction of the components leads to the difficult assembling of the components.